Marchant etal
j et propulsion engines



Aug 39, 1966 F. cz. 1 MARCH/WT ET AL 3,269,3M

JET PROPULS ION ENGINES 5 Sheecsheet l Filed Oct. 25, 1963 ur III ,1%

26 26/ 2/ /0 "Lftl Inventors Aug. 30, 1966 F. c. s. MARCHANT ETAL 3,269M

JET PROPULSION ENGINES Filed Oct. 25, 1965 5 Sheetsheet 2 Adame);

Aug- 30, 1966 F. c. MARcHAN-r ET Al. 3,269M

JET PROPULS ION ENGINES Filed Oct. 25. 1963 5 Sheets-Sheet 3 AJg- 30, 1966 F. c. 1. MARCHANT ET AL 3,269M

JET PROPULS ION ENGINES Filed Oct. 25, 1965 5 Sheets-Sheet 4 Aug- 30, 1966 F. c. l. MARCHANT ET AL 3,269JM JET PROPULS ION ENGINES Filed Oct. 25, 1963 5 Sheets-Sheet 5 Afform'yf United States Patent O 3,269,114 JET PROPULSION ENGINES Francis Charles Ivor Marchant, George Arthur Day, and George William Collins, Bristol, England, assignors to Bristol Siddeley Engines Limited, Bristol, England, a British company Filed Oct. 25, 1963, Ser. No. 319,014 Claims priority, application Great Britain, Oct. 30, `1962, 41,026/62 3 Claims. (Cl. 60-35.6)

This invention relates to gas -turbine jet propulsion engines of the kind comprising an .air compressor, a combustion system, a turbine system, a ducted fan upstream of the compressor, the fan and the air compressor being driven by the turbine system, a by-pass duct surrounding the engine which communicates at its upstream end with the delivery Vend of the fan duct, and means for burning fuel in the air flow through the by-pass duct.

According to the invention, a gas turbine jet propulsion engine comprises an air compressor, a combustion system, a turbine system, a ducted fan upstream of the compressor, the fan and the air compressor bei-ng driven by the turbine system, a by-piass duct surrounding the engine which communicates -at its upstream end with the delivery end of the fan duct, a tubular partition which divides the by-pass duct into radially inner and outer air passages, a valve for controlling the flow of air through one of the air passages, and means for burning fuel to heat the air ow through the other passage.

The effective area of discharge from the by-pass duct may be varied by adjusting the partition, so that the area is enlarged to accommodate the increased flow when the air in the by-pass duct is heated.

The downstream end portion of the vane may form a common wall between two concentric nozzles which constitute outlets from the inner and outer passages of the by-pass duct, which wall may be corrugated and/or pierced to promote intermingling of the nozzle discharges when the valve-controlled passage is open.

By way of example the invention will now be described with reference to the annexed diagrammatic drawings, of which:

FIGURE l is a composite ligure showing longitudinal half sections of a gas turbine engine having a divided bypass duct, the left and right hand halves showing the duct system adjusted respectively for normal engine operation and for duct burning,

FIGURE 2 is a cross-secti0n looking upstream from plane II-II of FIGURE l,

FIGURE 3 is a composite figure showing longitudinal half sections of a gas turbine engine having an alternative form of divided by-pass duct, which is provided with a corrugated nozzle,

FIGURE 4 is an end view looking upstream of FIG URE 3, and

FIGURE 5 is a composite ligure showing longitudinal half sections of a gas turbine engi-ne having a further alternative form of divided by-pass duct, in which the downstream section of the dividing partition is axially movable to vary the area of the outlet from the duct.

With respect to all the figures generally, in which like parts are denoted by like numerals, with the addition of sufxes a in FIGURES 3 and 4, and suxes b i-n FIG- URE 5, the gas turbine engine comprises a ducted fan 10, a multistage compressor 11, an annular combustor 12 indicated in outline only, a high pressure turbine rotor 13 arranged to drive the compressor 11, and a low pressure turbine rotor 14 arranged to drive the fan A10, the power from the respective turbines being transmitted through outer and inner concentric shafts 15, 16. The turbine exhaust gas Hows past the radial supports 17 for the tailcone 18, to be discharged through an annular nozzle 19 formed between the rounded tailcone 18 and a turbine diffuser casing 20.

The outer casing of the engine comprises an annular nose section 21, inner and outer intermediate sections 22, 23, a main section 24, and the diffuser `casing 20, all secured together. The outer casing of the engine is surrounded by an outer wall 25, the upstream end of which is bolted at 25 to the wall 26 of a duct 26 for the fan 10. The nose section 21 and the intermediate section 23 are supported from the outer wall 26 by radial vanes 27, 28 respectively. The vanes 27 extend inwards across the inlet to the compressor 11, and are secured to a supporting structure 29 mounted on a front bearing 30 for the shaft 16. The vanes 27 constitute exit guide vanes for the fan 10, whilst the large chord vanes 28 serve to straighten the air How in a by-pass duct 31 between the main section 24 of the outer casing of the engine and the outer wall 25. The delivery from the fan 10 is divided by the nose section 21 into an outer flow which ypasses through the duct 31, and an in-ner How which enters the intake of the compressor 11 to .pass through the engine.

Referring more especially to FIGURES 1.and 2, the duct 31 is divided into inner and outer passages 32, 33 by means of a tubular flow-dividing partition 34, which is shaped to follow substantially the contour of the adjacent divergent, parallel and convergent sections of the outer wall 25 of the duct 31. The inner passage 32, the burner passage, is provided with a circumferentially-spaced series of radial fuel injection tubes 35, which are mounted at 35 on the outer wall 25 and extend across the outer passage 33 in order to enter the inner passage 32. These tubes 35 `carry three concentric ame-stabilising rings or gutters 36 which lie within the inner passage 32, and are provided internally with liquid fuel passages 36 which deliver fuel to injection holes formed in their walls. The injector holes are located at the apices of the gutters 36, so as to discharge in the direction of air flow through the duct 31; alternatively they may be arranged to inject the fuel in the upstream sense. Igniters 37 are mounted at 37 on the outer wall 25, for ignition of the fuel-'air mixture in the inner passage 32 when required. The par* tition 34 is supported from the outer wall 25 by means of pairs of relatively slidable, co-operating members 8, 8 and 9, 9 the former pairs guiding radial thermal Vmovement and the latter pairs guiding axial thermal movement of the partition relative to the outer wall 25.

The upstream end of the partition supports an annulus of pivotable arcuate deector plates 38, which project upstream as far as the transverse plane at the beginning of a divergent se-ction 39 of the outer wall 25. A number of fluid-operated actuators 40, mounted on the di vergent section 39 of the outer wall 25, actuate the plates 38 by means of rams 41 and `links 42, in order to control the flow of air through the outer passage 33; the left hand half of FIGURE 1 showing the plates 38 in `their outer or closed position, whilst the right hand half shows the plates 38 in their inner or open position.

For normal operation, the engine may berun with the plates 38 in their closed position, in which their free ends seal against the outer wall 25 and obstruct. completely the ow of air through the outer passage 33,v whilst normal air flow continues through the inner passage 32.

When it is desired to increase the engine thrust by burning fuel in the inner passage of the duct, simultaneously the plates 38 are pivoted to their open position (as shown in the right hand ha-lf of FIGURE l) to permit air to ow through the outer passage 33, fuel is delivered to the radial tubes 35, and the igniters are caused to ignite the mixture of air and fuel in the inner passage 32. As a result the engine discharges three annular c0ncentric jets, an inner jet of turbine exhaust gas through the nozzle 19, an intermediate jet of burning gas through a by-pass inner nozzle 45, and an outer jet of relatively cold air through a bypass outer nozzle 46. The latter nozzle 46 is shaped to discharge the air therefrom with a pronounced radial inward component of motion, so as to promote mixing of the concentric air and gas jets.

By making the outer passage 33 of the duct the cold or non-burning passage, not only is the outer wall 25 of the engine insulated by the air ow in the outer passage 33 from the heat of combustion in the inner passage 32 and in the engine combustor 12, but also the dellector plates 38, their operating mechanism and the base portions of the tubes 35 and igniters 37 are cooled by the air flow through the outer passa-ge 33 during burning in the inner passage 32.

The outer wall of the nozzle 45, which is formed by the downstream end section of the tubular partition 34, may be corrugated to promote further the mixing of the air and gas jets during burning in the duct, and the jet noise is thus reduced.

In FIGURES 3 and 4, the arrangement differs from the preceding gures in the following respects: (a) the duct burning takes place in the outer passa-ge 33a, (b) the deflector plates 38a are controlled by actuators 40a located within the outer casing of the engine, (c) the fuel for duct burning is introduced through radial tubes 50, upstream of and separate from the guttering 36a, (d) the partition 34a is supported from the section 24a of the engine outer casin-g by longitudinally spaced sets of supports 52, and (e) the downstream end section of t-he partition 34a is formed with corrugations 52 extending inwards and outwards between the diffuser casing 20a and the outer wall 25a in order to form a corrugated nozzle 53.

The inner surface of the portion of the outer wall 25a which lies downstream of the fuel injection tubes 50 may be provided with a heat insulating liner (not shown), spaced inwards from the Wall and formed with injection slots for air flowing in the space between the wall and the liner.

The effective area of discharge from the nozzle 53 may be arranged to be varied, either by means of pivotable flaps, or by axial movement of the partition 34a, for example.

During normal operation (see the right hand half of FIGURE 3), the engine may be run with the plates 38a in their fully closed or innermost position whilst normal air flow continues through the outer passage 33a the burner passage, including the terminal corrugations 52. When it is desired to increase the engine thrust by duct burning (see the left hand half of FIGURE 3), the inner passage 32a is opened to the flow of air by pivoting the plates 38a to their fully open or outermost position, in which they extend in line with the main portion of the partition 34a, the fuel is delivered to the injection tubes 50, and the igniters 37a are caused to ignite the mixture of fuel and air in the outer passage 33a. As a result the engine now discharges two annular concentric jets, an inner jet of turbine exhaust gas through the nozzle 19a, and a mixed jet of intermingled air from the inner passage 32a and burning gas from the outer passage 33a through the corrugated nozzle 53.

In this arrangement, the engine outer casing is insulated from the duct burning by the cold air passing through the inner passage 32a, whilst the actuators 40a for the plates 38a are conveniently located adjacent to the delivery, from the compressor 11a, for actuation by compressed air tapped therefrom.

FIGURE is similar to FIGURE 3, except that the corrugateddownstream end portion of the tubular partition 34a is replaced by a plain convergent portion 55, which is separate from the remainder of the partition 34h and is arranged to be able to be moved axially by an actuator mechanism 5.6, in order to vary the effective l area of discharge from an outer nozzle 57 of the by-pass duct.

During normal operation, the engine may be run with the plates 3811 in their fully closed position and the partition section 55 extended downstream to reduce the effective area of the nozzle 57 (as shown in the left hand half of FIGURE 5 whilst normal air tlow along the outer passage 33b continues. When it is desired to increase the engine thrust by duct burning, the inner passage 32b, is opened to the flow of air by pivoting the plates 38h to their fully open position, the separate partition section 5S is retracted by causing it to slide upstream over the adjacent section of the partition 34h so as to increase the effective area 4of the nozzle 5'7 (as shown in the right hand half of FIGURE 5), fuel is delivered to the injection tubes 50, and the igniters 37b are caused to ignite the mixture of fuel and air in the outer passage 33h; the actuators 4Gb, the actuator mechanism 56, the fuel delivery to the tubes 50, and the igniters 37b being controlled by a coordinating system 6i). Consequently, the engine now discharges three annular concentric jets, an inner jet of turbine exhaust gas through the nozzle 1917, an intermediate jet of relatively cold air through the duct inner nozzle 58, and an outer jet of burning gas through the nozzle 57.

In all the engines illustrated, the fuel injectors in the burner passage of the by-pass duct are located in a diffuser section of the burner passage, thus promoting flame stabilisation.

In a further modification (not illustrated), the effective area of discharge from the by-pass duct may be varied in other ways, for example by mounting on the adjacent end portion of the flow-dividing partition, or on the side walls of the partition corrugations (if provided), pivotable flaps or the like which can be moved to restrict the ilow passing through the burner passage of the by-pass duct.

Any suitable form of fuel injection means and flame stabilisers may be used in the burner passage of the by pass d-uct.

In a further lmodification of the invention, the tubular partition is supported from the outer wall of the by-pass duct by means of a pair of diametrically opposite tunnel members or gullies of substantially U-section. The side portions of these tunnel members or gullies extend inwards from the outer wall to permit the intermediate portion of the gullies to be welded, or otherwise secured, to the outer surface of the tubular partition. Each gulley houses a hydraulic double acting ram mounted in an axially-extending cylinder which is supported from the intermediate portion of the gulley. The exposed ends of both rams pass up-streamwards through axial sealing sleeves, to emerge from the upstream ends of the gullies where they are connected to an operating ring which surrounds the annulus of deliector plates. A series of circumferentially-spaced links connect the operating ring to the deector plates at points intermediate between their free ends and their hinged ends, the arrangement being such that movement of the rams is transmitted through the operating ring and links to the deflector plates, to cause them to pivot in unison and thus control the flow of air through the inner passage of the by-pass duct.

We claim:

I. A gas turbine jet propulsion engine comprising a casing having an air intake and surrounding an air compressor, a combustion system downstream from the compressor, and a turbine system downstream from the cornbustion system, a ducted fan comprising a fan within a duct, upstream of the air compressor, means for driving the ducted fan and the air compressor from the turbine system, a by-pass duct surrounding the casing and communicating at its upstream end with the downstream end of the duct of said ducted fan, a fixed tubular partition which divides the by-pass duct into radially inner and outer air passages having separate outlet nozzles, means for burning fuel in lthe air flow through the inner passage, a valve adjacent the upstream end of the partition upstream from said fuel burning means for preventing flow through the outer passage only, and means for opening and closing the valve operable from the outer wall -of the outer passage.

2. An engine according to claim 1 in which the tubular partition .has a downstream end portion which forms a common wal1 between the two concentric outlet nozzles of the inner and outer air passa-ges of the by-pass duct, said downstream end portion being corrugated.

3. A gas turbine jet propulsion engine comprising a casing having an air intake and surrounding an air compressor, a combustion system downstream from the compressor, and a turbine system downstream from the combustion system, a ducted fan comprising a fan within a duct, upstream of the air compressor, means for driving the ducted fan and the air compressor from the turbine system, a by-pass duct surrounding the casing and communicating at its upstream end with the downstream end of the duct of said ducted fan, a tubular partition which divides the bypass duct into radially inner and outer air passages having separate concentric outlet nozzles, a valve for controlling the ow of air through one of the said inner and outer air passages, means for burning fuel to heat the air flow through the other of said inner and outer passages, means for increasing the effective area of discharge from that passage of the by-pass duct which contains means for burning fuel, when fuel is burnt in that passage, said means for increasing the effective area of discharge from said passage containing burning fuel comprising a movable partition section separate from the tubular partition but associated with the downstream end of said tubular partition, means for moving said movable partition section, means for delivering fuel to said passage, means for i'gniting said fuel Within said passage, and a coordinating system controlling the means for moving said movable partition section so that the elfective area of discharge from said passage is increased at the same time as fuel is delivered and ignited within said passage.

References Cited bythe Examiner UNITED STATES PATENTS 2,588,532 3/1952 Johnson 60--35.6 2,635,420 4/1953 Jonker 60-35.6 2,672,726 3/1954 Wolf et al 60-35.6 3,161,018 12/1964 Sandre 60-35.6

FOREIGN PATENTS 1,086,315 8/1954 France.

MARK NEWMAN, Primary Examiner.

D. HART, Assistant Examiner. 

1. A GAS TURBINE JET PROPULSION ENGINE COMPRISING A CASING HAVING AN AIR INTAKE AND SURROUNDING AN AIR COMPRESSOR, A COMBUSTION SYSTEM DOWNSTREAM FROM THE COMPRESSOR, AND A TURBINE SYSTEM DOWNSTREAM FROM THE COMBUSTION SYSTEM, A DUCTED FAN COMPRISING A FAN WITHIN A DUCT, UPSTREAM OF THE AIR COMPRESSOR, MEANS FOR DRIVING THE DUCTED FAN AND THE AIR COMPRESSOR FROM THE TURBINE SYSTEM, A BY-PASS DUCT SURROUNDING THE CASING AND COMMUNICATING AT ITS UPSTREAM END WITH THE DOWNSTREAM END OF THE DUCT OF SAID DUCTED FAN, A FIXED TUBULAR PARTITION WHICH DIVIDES THE BY-PASS DUCT INTO RADIALLY INNER AND OUTER AIR PASSAGES HAVING SEPARATE OUTLET NOZZLES, MEANS FOR BURNING FUEL IN THE AIR FLOW THROUGH THE INNER PASSAGE, A VALVE ADJACENT THE UPSTREAM END OF THE PARTITION UPSTREAM FROM SAID FUEL BURNING MEANS FOR PREVENTING FLOW THROUGH THE OUTER PASSAGE ONLY, AND MEANS FOR OPENING AND CLOSING THE VALVE OPERABLE FROM THE OUTER WALL OF THE OUTER PASSAGE. 